The mother of a nine-year-old boy hospitalized with head trauma has been arrested on assault and abuse charges after telling investigators she struck the boy with a baseball bat, authorities said. The boy has Down Syndrome and is unable to speak, a Cochise County Sheriff's Office spokeswoman said.

The woman, 34-year-old Nakia Brice, was arrested Wednesday and charged with four counts of aggravated assault and one count of child abuse and booked into the Cochise County Jail, said CCSO's Carol Capas.

Brice told authorities that she "lost control defending herself" with the bat when the boy was "acting out" by kicking, biting and scratching, Capas said.

The Sheriff's Office was contacted about the case Monday by staffers with the Arizona Department of Child Safety, Capas said, after the boy was taken to Banner University Medical Center in Tucson.

"An initial hospital report stated that the mother said the boy had fallen from a tree causing head injuries," Capas said in a news release.

The boy was in intensive care "being treated for severe head trauma and there were indications of past fractures in the rib and spine that were in various stages of healing," Capas said AZDCS told sheriff's investigators.

The boy, who is diagnosed with Down Syndrome and unable to speak, lives at a residence in Whetstone, north of Sierra Vista, with his mother and two other siblings, aged eight and two, Capas said.

"Because of the boy's inability to speak and the head trauma, detectives were not able to communicate with him for an interview," she said.

Brice's social media posts indicate that she adopted the boy from a Ukrainian orphanage in 2012.

The mother told investigators that "she struck the boy multiple times with the bat in the head and body," Capas said.

While searching the home, detectives found the baseball bat reportedly used in the incident, Capas said. CCSO is continuing to investigate the incident, she said.